For the following scenario, determine the dollar amount of the book$-$tax difference $($if any$)$ written as a positive number in $2017.$

On January $1,2015,$ Landmark Corporation offered its CFO $2,500$ NQOs options to purchase the company's at the same price offered by the public market on that day, $$11/$share $,$ at any date in the future after the CFO vests. The CFO will vest $25\%$ of its options in $2015,25\%$ in $2016,$ and vest the remaining portion in $2017.$ The CFO promptly exercised all of his options on December $31,2017$ when he was $100\%$ vested and turned around and sold all the shares for $$15/$share on the public market. Assume that on the grant date, Landmark Corporation estimated the value of the options would be $$4/$share$.$ The company uses a calendar year tax period.

a$.$ The book$-$tax difference in $2017$ is $$10,000.$

b$.$The book$-$tax difference in $2017$ is $$2,500.$

c$.$None of the answers given here.

d$.$ The book$-$tax difference in $2017$ is $$5,000.$

e$.$The book$-$tax difference in $2016$ is $$0.$

part $2$

a$.$ Not application as there is no book$-$tax difference

b$.$ Permanent

c$.$ Temporary

part $3$

a$.$Favorable

b$.$Unfavorable

c$.$ Not applicable as there is no book tax difference book